SYMMETRICAL SYNOVIAL-FLUID CELL CYTOKINE MESSENGER-RNA EXPRESSION IN RHEUMATOID-ARTHRITIS - ANALYSIS BY REVERSE TRANSCRIPTION-POLYMERASE CHAIN-REACTION

To investigate the complex intra-articular immune activity in rheumato id arthritis (RA), we analysed the expression of a wide range of cytok ine mRNAs in synovial fluid cells from patients with rheumatoid arthri tis. To minimize in vitro artefact, mRNA was rapidly extracted from sy novial fluid leucocytes taken from single joints of seven patients and simultaneously from both knee joints of four patients. Expression of interleukin (IL) 1 beta, IL-2, IL-4, IL-6, IL-8, IL-10, granulocyte-ma crophage colony-stimulating factor, tumour necrosis factor-alpha and i nterferon-gamma (IFN-gamma) was detected using the reverse transcripti on/polymerase chain reaction. The expression of cytokines varied betwe en patients. IFN-gamma mRNA was detected in 60% of the patients and IL -4 mRNA in 10%. Cytokine expression in both knees was very similar. Th ese results suggest that T-cel activity in RA is detectable using sens itive techniques and that the intra-articular immunopathology of RA is systemically very similar.